This invention relates to a light-emitting display device having an improved light diffusing film.
Light-emitting display devices are utilized in indicators of characters, marks and numerals. The light-emitting display device generally comprises a light-emitting element, a substrate on which the light-emitting element is disposed, a reflector which surrounds the light-emitting element, and a light diffusing film. The light diffusing film plays an important role in the point of uniformly diffusing the light emitted from the light-emitting element. In the past, a light-emitting display device as described in the following has been used. One light diffusing film consists of a light diffusing material which is a powdered material such as Al.sub.2 O.sub.3 SiO.sub.2 or CaCO.sub.3, and transparent material. Another light diffusing film consists of a transparent material having a rough face.
The brightness of the light-emitting display device using the above-mentioned light diffusing film, is decreased by the absorptive efficiency of the light diffusing film, in the case where the light diffusing material is such as Al.sub.2 O.sub.3, SiO.sub.2 or CaCO.sub.3. The brightness distribution of the light diffusing film is chiefly affected by the grain distribution and by the grain size of the light diffusing material. Therefore, the dispersion of the brightness and the brightness distribution widely vary in the prior art. As a result, it is difficult to produce a desirable characteristic for the light-emitting display device in the prior art.